Many electronic devices, including portable electronic devices such as but not limited to so-called smartphones and tablet/pad-styled devices, are configured to receive user input, at least in part, via a surface such as a display. A touch-sensitive display, for example, provides a way for a user to tap or swipe the display surface with a finger in order to express selections, input information, and so forth.
Many devices are configured to work specifically with a hand-held stylus in these same regards (either in lieu of the foregoing or in combination therewith). Some displays, for example, include a plurality of light-emitting transmitter/receiver pairs disposed along the sides of the display. By determining where a stylus breaks one of the corresponding light beams the device can determine a present location of the stylus and utilize that location information accordingly. Such an approach represents a passive location modality in that the behavior of the stylus as regards imparting location-determination information or otherwise participating in the location-determining process is passive.
In some instances the stylus comprises a non-passive stylus. In some cases this means the stylus includes one or more electrically-powered components that serve to interact with the display in a way that facilitates the display determining, for example, a point of contact between the stylus and the display. In general, a non-passive location modality pertains to stylus behavior that is other than a merely passive presence.
There are, in fact, a considerable number of non-passive location modalities presently known with more likely to become available. At least one reason for the considerable number of approaches in these regards is that no one approach is superior to all other approaches for all possible interactions. One approach, for example, might offer excellent results when the stylus contacts the surface while another competing approach offers better results when the stylus hovers close to the surface without contacting the surface.